Liabilities for Outstanding Claims, Losses and Loss Adjustment Expenses (Narrative) (Details) - USD ($) $ in Millions |
6 Months Ended | |
|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
|
| Liability For Claims And Claims Adjustment Expense [Line Items] | ||
| (Favorable) unfavorable loss and LAE development | $ (108.2) | $ (56.2) |
| Specialty [Member] | ||
| Liability For Claims And Claims Adjustment Expense [Line Items] | ||
| (Favorable) unfavorable loss and LAE development | (34.0) | (32.4) |
| Core Commercial [Member] | ||
| Liability For Claims And Claims Adjustment Expense [Line Items] | ||
| (Favorable) unfavorable loss and LAE development | (31.7) | $ (15.3) |
| Personal Lines [Member] | ||
| Liability For Claims And Claims Adjustment Expense [Line Items] | ||
| (Favorable) unfavorable loss and LAE development | $ (42.5) | |